TC 19S(GOMBE):forecast to make landfall North of Angoche/MOZ as a dangerous CAT 3 US shorlty after 12h,major flooding likely once inland,10/15utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 19S(GOMBE).

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: OVER THE PAST 6-12 HOURS, TC 19S HAS TAKEN A BIT MORE OF A SOUTHWESTERLY JOG THAN PREVIOUSLY ANTICIPATED. WHILE THE PREDOMINANT STEERING MECHANISM REMAINS THE SUBTROPICAL RIDGE (STR) TO THE SOUTH, A NEAR-EQUATORIAL RIDGE (NER) TO THE NORTH IS SLIGHTLY STRONGER THAN ANTICIPATED AND IS IMPARTING A STEERING PRESSURE FROM THE NORTH. HOWEVER, IN THE NEAR-TERM THE STR TO THE SOUTH IS ANTICIPATED TO STRENGTHEN AGAIN AND THE SOUTHWESTERLY MOTION SHOULD BE ARRESTED, WITH TC 19S RESUMING A MORE WESTWARD TRACK THROUGH 48H. THE SYSTEM IS FORECAST TO MAKE LANDFALL SHORTLY AFTER 12H IN THE VICINITY OF ANGOCHE, MOZAMBIQUE, THEN MOVING SLOWLY WESTWARD THROUGH 48H AS THE STEERING PATTERN WEAKENS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN VERY FAVORABLE THROUGH LANDFALL, WITH VERY WARM (30-31C) SSTS, LOW VWS AND STRONG OUTFLOW ALOFT, WITH A PEAK INTENSITY OF 100 KNOTS/CAT 3 US EXPECTED JUST PRIOR TO LANDFALL. ONCE INLAND, EVEN THOUGH THE SYSTEM WILL RAPIDLY WEAKEN, IT IS EXPECTED TO BRING COPIOUS AMOUNTS OF RAINFALL AND INDUCE MAJOR FLOODING OVER NORTH-CENTRAL MOZAMBIQUE AND SURROUNDING AREAS. BY 48H THE STEERING PATTERN WILL BEGIN TO SHIFT, AS THE STR TO THE SOUTH ERODES, MOVES EAST AND REORIENTS TO A NORTH-SOUTH AXIS AHEAD OF AN APPROACHING MID-LATITUDE TROUGH. IN RESPONSE, THE REMNANTS OF TC 19S WILL TURN SHARPLY POLEWARD AFTER 48H, AND SHOULD EMERGE BACK OVER WATER SHORTLY AFTER 72H. CONDITIONS OVER THE CENTRAL PORTION OF THE MOZAMBIQUE CHANNEL ARE EXPECTED TO BE FAVORABLE FOR TC DEVELOPMENT, AND THE REMNANTS OF TC 19S ARE FORECAST TO ONCE AGAIN INTENSIFY, PEAKING AT 45 KNOTS BY 120H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT THE SYSTEM CONTINUES TO CONSOLIDATE AND STRENGTHEN, BUT YET UNABLE TO SUSTAIN AN EYE IN THE EIR OR VISIBLE IMAGERY. A FORTUITOUS 101105Z AMSR2 PASS SHOWED WELL DEFINED, VERTICALLY STACKED MICROWAVE EYE FEATURES IN BOTH THE 37GHZ AND 89GHZ BANDS WITH DEEP CONVECTIVE BANDS WRAPPING IN THE FROM THE NORTH AND WEAKER, MORE ILL-DEFINED BANDING TO THE SOUTH. THE MICROWAVE IMAGERY SUGGESTS A COMPLETE EYEWALL, PARTICULARLY IN THE 36GHZ BAND, BUT WEAKER ON THE SOUTHWEST SIDE. THE HIGH RESOLUTION HWRF SHOWS A POCKET OF RELATIVELY DRIER AIR ON THE SOUTHERN SIDE OF THE EYE, AND THE MICROWAVE IMAGERY SEEMS TO CONFIRM THIS. THE PRESENCE OF THIS DRY AIR IS LIKELY ONE FACTOR KEEPING A LID ON THE INTENSIFICATION RATE OF THIS SYSTEM AT PRESENT. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON AN EXTRAPOLATION OF THE MICROWAVE EYE IN THE AMSR2 DATA. THE INITIAL CONFIDENCE IS ASSESSED WITH HIGH CONFIDENCE AS WELL, IN LINE WITH THE T4.5 DVORAK CURRENT INTENSITY ESTIMATES FROM BOTH PGTW AND FMEE, AS WELL AS AN AIDT ESTIMATE OF 74 KNOTS (WELL ABOVE THE ADT ESTIMATE IN THIS INSTANCE) AND THE MAXIMUM WIND OF 74 KNOTS SEEN IN THE AMSR2 WINDSPEED PRODUCT.

101105Z AMSR2 PASS SHOWED WELL DEFINED, VERTICALLY STACKED MICROWAVE EYE FEATURES IN BOTH THE 37GHZ AND 89GHZ BANDS WITH DEEP CONVECTIVE BANDS WRAPPING IN THE FROM THE NORTH AND WEAKER, MORE ILL-DEFINED BANDING TO THE SOUTH. THE MICROWAVE IMAGERY SUGGESTS A COMPLETE EYEWALL, PARTICULARLY IN THE 36GHZ BAND, BUT WEAKER ON THE SOUTHWEST SIDE.THE MAXIMUM WIND OF 74 KNOTS WAS SEEN IN THE AMSR2 WINDSPEED PRODUCT.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS VERY GOOD AGREEMENT THROUGH LANDFALL AND UP TO 36H, AND SUPPORTS THE JTWC FORECAST IN THIS SEGMENT OF THE FORECAST WITH HIGH CONFIDENCE. AS THE SYSTEM RAPIDLY WEAKENS AND THE STEERING PATTERN BEGINS TO SHIFT, THE MODEL GUIDANCE SHOWS DRAMATICALLY DECREASED CONFIDENCE, WITH A WIDE SPREAD OF SOLUTIONS, PARTICULARLY IN THE ENSEMBLE GUIDANCE. THE NAVGEM AND HWRF REMAIN THE TWO OUTLIERS, KEEPING THE SYSTEM OVER LAND FOR THE ENTIRE DURATION OF THE FORECAST. THE REMAINDER OF THE GUIDANCE PACKAGE CONCURS ON A TURN SOUTHEASTWARD AFTER 48H, BUT DIFFERS IN THE TIMING AND SHARPNESS OF THE TURN. THE JTWC FORECAST TRACK REMAINS CONSISTENT WITH THE PREVIOUS FORECAST, AND LIES ON THE EASTERN SIDE OF THE ENVELOPE WITH LOW CONFIDENCE AFTER 48H. INTENSITY GUIDANCE IS IN OVERALL GOOD AGREEMENT BUT HAS COME DOWN IN THE PEAK AGAIN, WITH ALL DETERMINISTIC GUIDANCE PEAKING BELOW 95 KNOTS BEFORE LANDFALL. THE RIDE RAPID INTENSIFICATION (RI) AID IS THE SOLE REMAINING RI AID TO BE TRIGGERED. THE JTWC FORECAST LIES ABOVE ALL OF THE GUIDANCE WITH THE EXCEPTION OF THE RIDE THROUGH LANDFALL, THEN SLIGHTLY ABOVE THE CONSENSUS THROUGH THE OVER LAND PHASE. THE MAJORITY OF THE DETERMINISTIC GUIDANCE INDICATES LITTLE TO NO INTENSIFICATION AFTER 96H, BUT THE COAMPS-TC, ECENS AND GEFS ENSEMBLE INTENSITY GUIDANCE INDICATES A 20-30 PERCENT PROBABILITY OF MODERATE INTENSIFICATION AND A 10-15 PERCENT PROBABILITY OF RI, LENDING INCREASED CONFIDENCE TO THE LONG-RANGE FORECAST. HOWEVER, THERE IS LOW CONFIDENCE IN THE FORECAST INTENSITY AFTER 48H DUE TO THE UNCERTAIN EFFECTS OF PROLONGED PERIODS OVER LAND AND THE ULTIMATE INTENSITY OF THE REMNANTS THAT EMERGE BACK OVER WATER.